The present invention relates to a surveying instrument, which can be easily installed at a reference position, and to a method to install, the surveying instrument.
In a conventional type surveying instrument, a measurement is carried out from a reference point already determined such as a reference point pile or the like. At the time of installation, it is necessary to determine where a machine center position of the surveying instrument (hereinafter referred as “machine reference point”) is positioned in space coordinates with respect to the reference point.
Conventionally, leveling is performed so that the surveying instrument is in vertical direction based on a leveling device incorporated in the surveying instrument. An operator looks in a centripetal telescope under a condition where the surveying instrument is made to stand vertically, and is set in such a manner than the reference point becomes the center of the centripetal telescope. That is, the surveying instrument is installed so that the machine reference point is positioned on a vertical line, which passes through the reference point, and the position on a horizontal plane is coincided with the reference point. After the installation, by actual measurement of a distance from the machine reference point to the reference point using a tape measure or the like, a position of the machine reference point with respect to the reference point is measured.
However, in a case of the conventional method, it is necessary at the same time to make the surveying instrument stand vertically and to perform positioning of the machine reference point and the reference point on the horizontal plane, and operations are necessary such as setting an installation position of a tripod and an installation surface of a surveying instrument main unit in a horizontal position. Further, on a ground surface such as soil and the like, which is soft and where the tripod sink in, there is a case where more time is required to set up the surveying instrument, and since the operator performs measurement by handwork with regard to the height of the machine reference point using a tape measured and the like, there is a possibility that an error occurs.
Further, instead of the operator looking in the centripetal telescope, there is a method which emit a laser beam in a vertically downward direction of the machine reference point and perform positioning on the horizontal plane of the machine reference point and the reference point by projecting the laser beam on the reference point. However, even in this case, it is necessary at the same time to make the surveying instrument stand vertically and to perform positioning of the machine reference point and the reference point on the horizontal plane, and has a similar problem to that of a case where the centripetal telescope is used.